1. Field of the Invention
The invention relates to testing for fiber optic transceivers. More particularly, the invention relates to determining the high speed performance or behavior of fiber optic transceivers and transceiver modules.
2. Description of the Related Art
Fiber optic transceivers and fiber optic transceiver modules are devices that both transmit and receive optical signals. During the process of fabricating fiber optic transceivers, when fiber optic transceivers are assembled and tested, a relatively large amount of time is spent characterizing the high speed behavior or high speed performance of the transceiver over an extended range of transceiver operating temperatures. That is, testing the transceiver to confirm whether its high speed performance characteristics are acceptable over the likely range of transceiver operating temperatures typically requires a relatively large amount of time compared to the overall time for transceiver fabrication, assembly and other testing.
Conventionally, the transceiver module initially is heated to a particular testing temperature, typically within a range of typical transceiver operating temperatures. The transceiver module then must be given sufficient time to stabilize at that initial temperature. The transceiver then is subjected to a series or suite of high speed performance tests to measure its high speed behavior or performance characteristics. Such high speed tests include Bit Error Ratio (BER) tests under a number of different input signal conditions, such as adding jitter and adding drive current. Another high speed test is a small signal frequency response test under a number of different input signal conditions. Typically, each high speed test requires a different set-up procedure, often involving different test equipment. After the suite of high speed tests are performed at the initial temperature, the transceiver module is heated to a different temperature, the transceiver is allowed to stabilize at the new testing temperature, and the suite of high speed tests are repeated at the new testing temperature.
Since transceivers typically are tested at several different temperatures over the range of transceiver operating temperatures, the overall testing procedure typically is relatively time consuming. For example, it takes a relatively long time to heat the transceiver module to each of several different testing temperatures and to allow the transceiver to stabilize at the given testing temperature. Moreover, the time required to perform each of the suite of high speed tests at each different temperature adds to the overall testing time. The relatively long period of time required to determine the high speed behavior of fiber optic transceivers adversely affects the production rate, and ultimately the cost, of the transceiver modules.